Oceanographer (AGS-3), formerly Corsair 11, was built in 1899 by W. and A. Fleteher Co., Hoboken, N.J. Except for a brief period of commissioned service during World War I, she served as a luxury yseht for J. P. Morgan until 1930. After lowering financier Morgan's pennant, the "floating castle" served with the Coast and Geodeti Survey, as Oceanographer.

She was acquired by the Navy from the Coast and Geodeti Survey at Norfolk, Va. 7 April 1942, briefly renamed Natcha (PG-85); renamed Oceanographer (AGS 3); rerigged and outfitted at Norfolk Shipbuilding and Drydock Co. for survey duty; and commissioned 15 August. Work was completed 28 August and Comdr. Henry B. Campbell, USCGS, assumed command, with Lt. Comdr. Myron W. Graybill, USN, as Executive Officer.

After shakedown in the Chesapeake, Oceanographer steamed for New York 3 October to join a convoy enroute Cristobal, C.Z. She transited the Canal, and at San Pedro, Calif., reported for duty to CINCPAC. Upon completion of repairs at San Pedro, she got underway for Seattle, Wash. She encountered a severe storm off Astor~a, Ore., necessitating further repairs at Winslow Marine Railway Co., Bainbridge Is., Wash. Proceeding to Kodiak via the Inside Passage, she reported to the Alaskan Command with no sound or radar gear, a very short eruising radius, and limited potable water capabilities, considered generally unsuitable for Aleutian duty.

Oceanographer returned to Seattle 25 December 1942 for additional repairs. After towing a YCV from Seattle to San Francisco, she was assigned to the Matson Navigation Co. for repairs. Comdr. Graybill assumed command 2 March 1943 and the following day Oceanographer got underway for Pearl Harbor, where sound gear was installed and necessary alterations made.

The survey ship departed Pearl Harbor escorting several LSTs and plotted a course for Noumea, New Caledonia. As her first war zone assignment she surveyed Havannah Passage, New Caledonia. Upon completion of the Havannah Passage charts the ship made three other surveys in the vicinity of Noumea, erecting numerous beacons and planting many buoys. On 1 November she proceeded to Guadalcanal via Esplritu Santo to produce charts of that island's northern coast. She also surveyed Munda Bar and neighboring anchora~es at Munda, New Georgia, B. S. I. At various times subchasers and APCs assisted in the surveys and dispatched triangulation parties to islands in the vicinity.

During her sixteen months in the South Pacific, Oceanographer produced fifteen charts, each requiring from one to three million soundings. Much of the data compiled was the first of any acouracy for the area, and it contributed greatly to the sueeess of many amphibious operations.

Ordered to Pearl Harbor 3 June 1944 for badly needed repairs, she was sent on to San Pedro, Calif. 27 June. Upon completion of arrival inspection, it was decided to decommission and scrap her. Oceanogra~her decommissioned 22 September, was struck from the Naval Register 14 October, and, in accordance with the agreement executed with J. P. Morgan, Jr., broken up for scrap.